Caesarean section rates and adverse neonatal outcomes after induction of labour versus expectant management in women with an unripe cervix: a secondary analysis of the HYPITAT and DIGITAT trials

Abstract

Between 20% and 25% of pregnancies require induction of labor (IOL), especially in situations that indicate better outcomes for mother and child if the pregnancy is not further prolonged. However, the effectiveness of IOL is subject to considerable debate because of concerns regarding the associated high rates of cesarean deliveries in women with an unripe cervix. The objective of this study was to evaluate the risk of cesarean delivery (CD) and adverse neonatal outcome rates after IOL or expectant management in women with an unripe cervix at or near term. This study used combined data from the multicenter, open-label, randomized controlled trials (RCTs) HYPITAT and DIGITAT. The inclusion criteria were women with hypertensive disease (HYPITAT trial) or suspected fetal growth restriction (DIGITAT trial) and a Bishop score of 6 or less. The study compared the outcomes after IOL and expectant management. The primary outcomes of this study were CD and a composite adverse neonatal outcome (defined as 5-minute Apgar score <=6 and/or arterial umbilical cord pH <7.05 and/or neonatal intensive care unit admission and/or seizures and/or perinatal death). Results of the study revealed that of 1172 women with an unripe cervix 572 women had IOL and 600 women had expectant management. It was noted that there was no significant difference in the overall CD rate (difference, -1.1%; 95% CI, -5.4 to 3.2). Also, IOL did not increase CD rates in women with Bishop scores from 3 to 6 (difference, -2.7%; 95% CI, -7.6 to 2.2) or adverse neonatal outcome rates (difference, -1.5%; 95% CI, -4.3 to 1.3). Results, however, noted that there was a significant difference in the rates of arterial umbilical cord pH less than 7.05 favoring IOL (difference, -3.2%; 95% CI, -5.6 to -0.9). The study concludes that there is no evidence that IOL increases the CD rate or compromises neonatal outcome as compared with expectant management in term or near-term pregnancies complicated by intrauterine growth restriction (IUGR), gestational hypertension, or preeclampsia. In addition, it was noted that there is no basis for concern regarding any increase in risk of failed induction in women with a Bishop score from 3 to 6.